GEDmatch is popular among people studying their family trees and adult adopted children looking for their birth parents. You upload your data file from a testing service, and the system helps you find other people whose DNA matches yours. It’s a small database, so it’s unlikely you’ll get a direct hit, but chances are you’ll at least find a few distant cousins to help narrow down your search.

There are other DNA databases, too, and it’s a safe bet that law enforcement and forensics companies are pursuing similar strategies wherever they can.

What’s Next

A hundred samples in a month is nothing. If this technique works, it seems likely to become routine for police departments across the country. GEDmatch recently updated its policy to explicitly allow law enforcement to search the database, with a few restrictions:

When you upload Raw Data to GEDmatch, you agree that the Raw Data is one of the following:

Your DNA;

DNA of a person for whom you are a legal guardian;

DNA of a person who has granted you specific authorization to upload their DNA to GEDmatch;

DNA of a person known by you to be deceased;

DNA obtained and authorized by law enforcement to either: (1) identify a perpetrator of a violent crime against another individual; or (2) identify remains of a deceased individual;

An artificial DNA kit (if and only if: (1) it is intended for research purposes; and (2) it is not used to identify anyone in the GEDmatch database); or

DNA obtained from an artifact (if and only if: (1) you have a reasonable belief that the Raw Data is DNA from a previous owner or user of the artifact rather than from a living individual; and (2) that previous owner or user of the artifact is known to you to be deceased).

‘Violent crime’ is defined as homicide or sexual assault.

However, GEDmatch can change the policy at any time.

On the one hand, it’s pretty cool that murderers and rapists can be brought to justice, and families can get closure on their missing loved ones. On the other, I never agreed to put my DNA in a law enforcement database—but now snippets of it are probably already there thanks to third or fourth or fifth cousins who had no idea their Ancestry file would ever be used this way.